Cantilevered Flange Die Insert for a Rotary Cam Having a Reduced Diameter Portion

ABSTRACT

A sheet metal forming die set includes a rotary cam that is received in a cavity of one of the dies. The rotary cam has a cylindrical body portion and a bullet nose portion that is smaller in diameter than the body portion. A cantilevered insert is provided on the die adjacent to the bullet nose portion.

BACKGROUND

1. Technical Field

This application relates to a sheet metal forming die having a rotary cam that is used to form complex shapes.

2. Background Art

Sheet metal panels are formed on die sets that form a sheet metal blank into a desired shape in a series of steps including dies for drawing, trimming, flanging, piercing and other operations in a series of steps. Traditionally, such die sets included an upper die that is reciprocated relative to a fixed lower die to perform a desired operation on a sheet metal panel or blank. Forming cams may be carried by the upper die to form various surfaces that may not be easily formed with a die that moves in a vertical reciprocating motion. Rotary cams are used to support or back up portions of panels that define undercuts or other complex shapes. Rotary cams are cylindrical in shape and are pivoted between a forming position and a retracted position. Rotary cams are pivoted to the retracted, or unload, position to permit the panel to be removed from a die after forming around an undercut or complex area.

To form complex shapes on some panels, it was previously necessary to provide multiple dies for flanging complex curve shapes. Using multiple dies for flanging increases dimensional variation and may adversely affect the appearance of the finished panel due to variation in part to die locations. Conventional rotary cams when used in flange dies may not be capable of directly flanging the part due to the die/part interference when the rotary cam is retracted to unload the part. This is an inherent limitation of conventional rotary cam designs and may result in flange bypass locations on complex parts. Flange bypass locations are areas where there are gaps between flanging surfaces on a die used to form a flange. Flange bypass locations may also adversely affect flange appearance in the finished panel.

The tooling approach developed by Applicants addresses the above problems and others that will be apparent to one of ordinary skill in the art.

SUMMARY

The die set developed by Applicants includes a rotary cam that is assembled within a cradle in a lower die. A die insert is cantilevered over the rotary cam on at least one end of the rotary cam that has a reduced diameter. The die insert rests on the top of the reduced diameter portion of the rotor to provide support for the cantilevered die insert during a flanging operation. The die insert and reduced diameter end of the rotary cam are machined to a matching frustoconical or spherical shape that defines a common radius as viewed normal to the rotor center line. The radius may vary over the length of the insert. Every section is a true radius to permit rotation of the rotary cam including the reduced diameter section about the pivot access of the rotary cam. The rotary cam has an outer surface that is cylindrical in shape and has a cylindrical radius. A radius of the bullet nose, or reduced diameter section, is between zero and the radius of the cylindrical body portion of the rotor.

The insert and reduced radius portion of the rotary cam permits direct flanging over areas of a panel that are back angled to the direction that the rotor retracts. The increased flexibility provided by the cantilevered die insert and reduced radius portion of the rotary cam can be used to reduce the number of flange bypass locations on a panel. The cantilevered die insert facilitates providing a variable diameter rotor in a critical location.

According to one aspect of the disclosure, a die set is provided for forming a panel in a press. The die set includes an upper die that is adapted to be set in the press. A lower die is also adapted to be set in the press to cooperate with the upper die. A rotary fill cam is assembled to the lower die. The rotary fill cam is pivoted about an axis and includes a cylindrical portion and a reduced diameter portion on at least one end. A cantilevered flange die insert is secured to the lower die to extend over the reduced diameter portion of the rotary fill cam. The cantilevered flange die insert fills the space between the upper die and the reduced diameter portion of the rotary fill cam.

According to another aspect of the disclosure, a rotary fill cam is operatively assembled to a die. The rotary fill cam includes a body portion that is assembled to the die to pivot within the die. A bullet nose portion is provided on one end of the body portion that pivots with the body portion. The die has a cantilevered flange die insert that overhangs the bullet nose portion of the rotary fill cam and is supported by the bullet nose portion in a forming operation.

According to yet another aspect of the disclosure, a die assembly is provided that is used to form a panel. The die defines a cavity in which a rotary cam is received. The rotary cam has a cylindrical portion and a re-entrant portion. A cantilever extension is attached to the die and extends into the re-entrant portion. A first forming surface is provided on the extension and a second forming surface is provided on the rotary cam that is rotated to a position adjacent to the first forming surface to form a portion of the panel.

According to other aspects of the disclosure, the re-entrant portion may have a partially spherical convex surface and the extrusion may have a partially spherical concave surface that are assembled together. A second die may be provided that includes a third forming surface that engages the panel on the opposite side of the panel from the first and second forming surfaces when they are adjacent to each other. The rotary cam rotates the second forming surface to a position that is not adjacent to the first forming surface to facilitate removal of the panel from the first die.

These and other features and aspects of the disclosure will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a lower die that includes a rotary cam disposed in a cavity, or cradle, defined by the lower die;

FIG. 2 is a diagrammatic elevation view showing a die insert cantilevered over a re-entrant portion of a rotary cam with an upper die and cam former;

FIG. 3 is a perspective view of a rotary cam having a re-entrant portion formed on one end;

FIG. 4 is a fragmentary perspective view of a portion of a cantilevered insert and rotary cam; and

FIG. 5 is a fragmentary perspective view of a rotary cam and cantilevered insert.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

Referring to FIG. 1, a lower die 10 is illustrated that includes a rotary cam 12 that is received in a cavity 14, or cradle, that is defined by the lower die. The rotary cam 12 includes a cylindrical body portion 18 and a bullet nose portion 20. Conventional rotary cams are generally cylindrical in shape and do not include any portions that are of reduced radius or diameter relative to the cylindrical portion 18. A cantilevered extension 22 is assembled to the lower die 10 to extend into and fill the recess created by the reduced diameter nose portion 20.

Referring to FIG. 2, a diagrammatic representation of the rotary cam 10 in the area of the nose portion 20 and cantilevered extension 22 is illustrated. The rotary cam 12 is rotated about an axis “A” to the forming position as shown in FIG. 2. The cylindrical body portion 18 has a radius “R”. An insert, or extended, forming surface 26 is provided on the cantilevered extension 22. A cam, or extended, forming surface 28 is provided on the nose portion 20. A panel 30 is formed against the insert forming surface 26 and the cam forming surface 28 when they are disposed adjacent to one another.

The panel 30 may also be formed against an undercut forming surface 32 that is also provided on the nose portion 20 of the rotary cam 12. An undercut forming surface 32 may also be provided on the nose portion 20. The panel 30 may be formed against the undercut forming surface 32 when the panel 30 is formed.

An upper die 36 reciprocates relative to the lower die (not shown in FIG. 2) to fully form a flange against the insert forming surface 26 and the cam forming surface 28. A cam former 38 may be used to form the panel 30 in the position shown in phantom lines in FIG. 2 to the position shown in solid lines against the undercut forming surface 32. In this position, removal of the panel 30 from the die would be impossible without the use of the rotary cam 12. The rotary cam 12 is rotated away from the panel 30 to provide clearance for removal of the panel 30 from the lower die 10.

Referring to FIGS. 3 and 4, a rotary cam 12 made according to one embodiment of the present invention is shown. The rotary cam 12 includes a cylindrical portion 18 and a nose portion 20. The nose portion 20 includes a convex spherical support surface 40 that is used to support the cantilevered extension 22 that has a complimentary concave spherical surface 42. The spherical support surface 40 supports the cantilevered insert 22 during the forming operation so that the insert is not damaged when the panel 30 is formed by the upper die.

Referring to FIG. 5, the rotary cam 12 is shown in conjunction with the cantilevered extension 22. The nose portion 20 is of reduced diameter as compared to the cylindrical portion 18. The reduced diameter nose portion 20 may also be referred to as a re-entrant portion relative to the cylindrical body portion 18. The insert 22 defines an insert forming surface 26 that cooperates with a cam forming surface 28 formed on the nose portion 20. An undercut forming surface 32 is also shown adjacent the cam forming surface 28 that permits the flange area to be formed beneath the cam forming surface 28 as previously explained with reference to FIG. 2.

Although embodiments of the invention have been disclosed, it will be apparent to persons skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents thereof are intended to be defined by the following claims. 

What is claimed:
 1. A die set for forming a panel in a press comprising: an upper die; a lower die cooperates with the upper die; a rotary fill cam is assembled to the lower die, the rotary fill cam is pivoted about an axis, the rotary fill cam having a cylindrical portion and a reduced diameter portion on at least one end; and a cantilevered flange die insert is secured to the lower die to extend over the reduced diameter portion of the rotary fill cam filling the space between the upper die and the reduced diameter portion of the rotary fill cam.
 2. The die set of claim 1 wherein the reduced diameter portion of the rotary fill cam is formed in the shape of a bullet nose that is provided on one end of the cylindrical portion.
 3. The die set of claim 1 wherein the rotary fill cam defines a first extended forming surface and the cantilevered flange die insert defines a second extended forming surface of the lower die.
 4. The die set of claim 3 wherein the first extended forming surface of the rotary fill cam is disposed adjacent the second extended forming surface of the lower die surface when the panel is formed in the press.
 5. A rotary fill cam that is operatively assembled to a die, the rotary fill cam comprising: a body portion that is assembled to the die to pivot within the die; a bullet nose portion that is provided on one end of the body portion and that pivots with the body portion; and wherein the die has a cantilevered flange die insert that over hangs the bullet nose portion of the rotary fill cam and is supported by the bullet nose portion.
 6. The rotary fill cam of claim 5 wherein the body portion is cylindrical.
 7. The rotary fill cam of claim 6 wherein the cylindrical body portion has an axis about which the body portion pivots, wherein the outer periphery of the body portion is disposed at a radius R from the axis and wherein the bullet nose portion defines a forming surface that is disposed at a distance from the axis that is less than R.
 8. The rotary fill cam of claim 5 wherein the die has a die surface, and the bullet nose portion defines a first extended portion of the die surface.
 9. The rotary fill cam of claim 8 wherein the cantilevered flange die insert defines a second extended portion of the die surface.
 10. A die assembly used to form a panel comprising: a die that defines a cavity; a rotary cam received in the cavity, the rotary cam having a cylindrical portion and having a re-entrant portion; a cantilevered extension attached to the die and extending into the re-entrant portion; a first forming surface provided on the cantilevered extension; and a second forming surface provided on the rotary cam that is rotated to a position adjacent to the first forming surface to form a portion of the panel.
 11. The die assembly of claim 10 wherein the re-entrant portion has a partially spherical convex surface and the extension has a partially spherical concave surface that is assembled over the partially spherical convex surface.
 12. The die assembly of claim 10 wherein the re-entrant portion has a partially spherical convex surface and the extension has a partially spherical concave surface that is assembled over the partially spherical convex surface.
 13. The die assembly of claim 10 wherein the first and second forming surfaces cooperate to back up a compound flange portion of the panel.
 14. The die assembly of claim 10 wherein the first forming surface is arcuate in shape and is disposed on one edge of the extension, and further wherein the second forming surface is arcuate in shape and is disposed on one edge of the rotary cam.
 15. The die assembly of claim 10, further comprising a second die that includes a third forming surface that engages the panel on the opposite side of the panel from the first and second forming surfaces when they are adjacent to each other and wherein the rotary cam rotates the second forming surface to a position that is not adjacent to the first forming surface to facilitate removal of the panel from the first die. 